🚀 go-pugleaf

RetroBBS NetNews Server

Inspired by RockSolid Light RIP Retro Guy

Article View: borland.public.cppbuilder.database.multi-tier
Article #80

Re: datasnap access violation

#80
From: Mark Guerrieri
Date: Thu, 31 Mar 2005 22:25
27 lines
2283 bytes
> i have used datasnap remote data module to create a multi tier database
> application...
> i have placed in the remote data module an ado connection ,4 ado tables
and
> 4 dataset providers..i
> have also (of course a form1)..i want to when i click the start/shutdown
> button on the Form1 to stop or start the datasnap server...when i try to
> stop the adoconnection (with connected->false,or cancel()) i get an access
> violation,same for the tables(adotable->active=false) the same for the
> dataset providers..it seems that i cant change  anything in the remote
data
> module by using a button on the form1...of course i have included the file
> header(<include...)...what am i doing wrong?
> the funny thing is that if i put an adoconnection in my form and use a
> button to start stop it ,it works perfectly!
>

By design, the DataSnap server should be running on one machine (with no
user interface) and the client that accesses it should be running on another
machine.  At the least, they would be running in seperate prcesses on the
same machine.  Either way, there is no way to directly access the
properties/methods of the components on the RDM from the client app.  Your
access violations are most likely the result of accessingg NULL/undefined
pointers, since the form in the client has no access to the components in
the RDM.

Mark
Technical Details
Message-ID: <424c78d6$1@newsgroups.borland.com>
Path: arc1-ca.pugleaf.net!g2news1.google.com!news3.google.com!news4.google.com!newshub.sdsu.edu!logbridge.uoregon.edu!newsfeeds.ihug.co.nz!ihug.co.nz!newsgroups.borland.com!not-for-mail
References: <423ff302@newsgroups.borland.com>

Show Full Headers
Complete Article Headers
X-Google-Thread: fcd2b,819ac6fcd9b2eba
X-Google-Attributes: gidfcd2b,public
X-Google-Language: ENGLISH,ASCII-7-bit
From: "Mark Guerrieri" <mguerrieri@nospam_cmsgrp.com>
Newsgroups: borland.public.cppbuilder.database.multi-tier
References: <423ff302@newsgroups.borland.com>
Subject: Re: datasnap access violation
Date: Thu, 31 Mar 2005 17:25:34 -0500
Lines: 29
Organization: Creative Marketing Strategies
X-Priority: 3
X-MSMail-Priority: Normal
X-Newsreader: Microsoft Outlook Express 6.00.2800.1158
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165
NNTP-Posting-Host: 209.50.174.82
Message-ID: <424c78d6$1@newsgroups.borland.com>
X-Trace: newsgroups.borland.com 1112307926 209.50.174.82 (31 Mar 2005 14:25:26 -0800)
Path: arc1-ca.pugleaf.net!g2news1.google.com!news3.google.com!news4.google.com!newshub.sdsu.edu!logbridge.uoregon.edu!newsfeeds.ihug.co.nz!ihug.co.nz!newsgroups.borland.com!not-for-mail